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Joonas Heikkinen's avatar
Joonas Heikkinen
Copper Contributor
May 31, 2018

Issues with adding @mydomain.onmicrosoft.com proxyaddresses

Greetings, I have been struggling with this proxy address issue during the past few days and can't seem to find a way around it. Hope you guys can help. So the issue is I'm not able to add @mydoma...
exchange
office 365
Sampathkovuri's avatar
Sampathkovuri
Copper Contributor
Mar 02, 2022

Hello..

I had the same issues which I could able to resolve.. Firstly, Alias in office365 is synced from mailnickname in onprem AD and appends the onmicrosoft domain. Also, alias in O365 will get synced from onprem AD only once as per the microsoft design so we can't rename later. However, there is a workaround to fix this issue.

 

1) Rename the mailnickname from SamAccountName to UPN prefix
2) Move the user to lostandfound OU or Any OU which is not under Azure AD Connect sync scope
3) Run the sync manually using the command Start-AdSyncSyncCycle -PolicyType Delta
4) Once sync is completed, the user will get deleted from Azure AD. So login into Office365 Admin center and open the deleted Users... Restore the user which you are targetted(you can choose the password)

5) After restoring the user, user became cloud user so assign any license to appear the user in exchange admin center.

6) Since the user is not synced from onprem AD and became cloud user, rename the alias as you wish

7) Now move the user back to same OU where it was earlier.

😎 Run the delta sync again.

9) Now the restored user becomes on prem AD.

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